A previous report has described a theoretical model based on random utility theory for the distribution of journeys to work for an existing set of houses and workplaces. One version of the model is equivalent to a gravity model with negative exponential deterrence function, and the present report describes an empirical application of this using 1971 census data for the Manchester conurbation. The calibrated model is seen to reproduce satisfactorily the observed distribution of work journeys. It predicts that house rents will tend to fall with distance from the city centre, with small peaks at outlying centres of employment. The pattern of salaries is similar but less pronounced, with much smaller variations. The model is used to simulate the medium-term effect upon work journeys of changing travel costs. For example, it is found that a uniform 1 per cent increase in the cost of travel reduces mean trip length by 0.75 per cent and increases travel expenditure by 0.25 per cent; consumer surplus is reduced by 1.00 per cent of total travel expenditure. The model also simulates policies which alter the distribution of houses and jobs, and it is found that consumer surplus increases when jobs are dispersed from the city centre or new housing is built near the city centre. (Author/publisher)
Samenvatting